The present invention relates to improvements in portable machines for performing cuts, particularly rectilinear and curvilinear cuts, in stone, marble, granite and the like.
Machines by which slabs of various materials are cut along a substantially arbitrary path that require the use of a template for guiding the machine itself on the cutting tool are well known in the art.
These known machines use as afore said a template for guiding the cutting tool, a diamond-wheel or the like, and if this is acceptable for mass production which entails a large number of machined pieces, this is absolutely unacceptable for single-piece operations both in respect of the set-up times and the costs for the preparation of the templates. This is particularly true when these operations are carried out by a craftsman who should change the template for each machining operation.
Presently, small machines for cutting stone, marble and the like, are known. However, even if they are reasonably light and convenient, cuts on millings along arbitrary curvilinear path with the required precision can not be performed.
It would be therefore particularly advantageous to provide a portable machine by which it is possible to follow an arbitrary cutting path either rectilinear or curvilinear, allowing the manual guidance of the cutting tool with a great ease and without the need of using a template.
The portable machine according to the present invention basically comprises a frame connected to a supporting member carrying the machine over a slab of stone or the like to be machined, the frame carrying a motor for driving the cutting or milling tool and a handle for guiding the machine and the tool along a desired working path.
The supporting member carrying the machine over the slab to be machined is provided on the surface faring the slab with a plurality of rolling ball bearings having a low friction coefficient so as to allow the user to operate easily the machine over the top surface of the slab to be machined.
In the known machines of this kind, however, the frame of the machine and the member supporting the same over the surface of the slab to be machined are angularly fixed both in azimuth and elevation and for this reason the shifting of the machine over the surface of the slab to be machined is rather difficult. Moreover, if with a machine of the known type it is desired to mill agroove with a variable depth or width, for instance for machining recesses for inlay works, such operation would be very difficult and even at all impossible.
U.S. Pat. No. 1,542,127 discloses improvements in sawing machines in which a toothed cutting blade is moved reciprocatively and in which it is possible to guide the saw blade between lubricated blocks adjustable in the base. Further, means are provided to adjust the length of the stroke of the saw that allows to adjust consequently the depth of penetration of the blade into a work piece. Also provided is a supporting member with a plurality of rolling ball bearings allowing the free movement of the supporting member over the workpiece.
GB-A-0 810 682 discloses an apparatus for cutting grooves in brickworks, comprising an electric motor mounted on a trolley driving through gearing a horizontal cutter or disc for cutting a slot in a wall. The trolley carries castors associated to means for the adjustment of the height at which the slot is to be cut, further and the depth of the cut is controlled by an adjustable fender mounted on the trolley.
The object of the present invention is therefore to provide a portable machine for cutting and/or milling slab materials such as stone in general, marble, granite and the like, by which it is possible to overcome the above disadvantages and to perform cuts and/or millings of any depth and following any path or contour with a minimum effort by the operator.
According to the invention, the member supporting the machine over the surface to be machined is rendered freely movable but connected to the frame of the machine carrying the motor and the cutting tool, while a guide handle allows to guide the frame itself, and thus the machine, with both hands, thus decreasing the effort of the operator while permitting to follow any path for cutting or milling the slab to be machined, without using a template.
According to the invention, the frame of the machine cooperates with the supporting member through a swivel connection device having more than a single degree of freedom that allows to displace in azimuth the supporting member with respect to the cutting tool and to adjust the slant angle of the same, and the sinking of the cutting tool into the slab to be machined.
According to the invention, a portable machine is provided for performing cuts, particularly rectilinear or curvilinear cuts, in stone, marble, granite and the like, which comprises:
a supporting member arranged for movement over the top surface of a stone or the like to be machined; PA1 a frame connected to the supporting member through a connecting block, the frame supporting motor means and transmission means for driving a cutting tool; PA1 a handle for moving the machine over the surface of stone or the like to be machined; and PA1 means for adjusting the sinking of the cutting tool into the stone, the supporting member being provided on the surface towards the stone with a plurality of rolling-ball bearings to allow the free movement of the supporting member, frame and cutting tool for following a rectilinear or curvilinear path, PA1 the connecting block cooperating with coupling means for allowing a free rotation of the frame with respect to the supporting member.